AB1469 HEPATITIS C IN IDIOPATHIC INFLAMMATORY MYOPATHIES: DIFFERENCES IN DISEASE PRESENTATION AND PATIENT MANAGEMENT
Authors: A. Valle, S. Mahmood
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> It is known that Hepatitis C (HCV) can cause many extrahepatic manifestations which overlap with rheumatic diseases. New evidence is emerging that both HCV and idiopathic inflammatory myopathies (IIMs) may have a common mechanism through B cell expansion and dysfunction [1,2]. <h3>Objectives</h3> Our aim was to describe the prevalence of HCV in patients with IIM and to compare myositis disease course, organ involvement, and rheumatologic treatment response between IIM patients with and without HCV. <h3>Methods</h3> A registry was created of Montefiore Medical Center patients that met 2017 EULAR/ACR classification criteria for IIM. Demographics, IIM type, antibodies, clinical manifestations, comorbidities, and rheumatologic treatment history were documented. HCV antibody, viral load, and hepatitis treatment history were noted. Rheumatic medication failure was defined by rheumatologist, discontinuation due to adverse effects, or medication change within 3 months while medication control was defined by documented clinical improvement. Statistical analyses included two-sample t-test, Chi-square tests or Fisher's exact tests were used to compare the categorical variables as appropriate and signed rank test. <h3>Results</h3> Of 153 patients in the registry, 130 (85%) had been screened for Hepatitis C and 11 (8.5%) had evidence of current or past HCV infection. Comparison of demographics, myositis types, presentation, and comorbidities revealed those with HCV were more likely to be male (p = 0.03) and have inclusion body myositis (IBM) (p = 0.002, Figure 1). Despite comparable numbers of dermatomyositis (DM), those with HCV were less likely to exhibit the classic dermatologic findings of DM, including Grotton's papules (p = 0.05), heliotrope (p = 0.05), or others rashes such as holster, shawl, V sign (p = 0.02). Interstitial lung disease (ILD) was less prevalent in individuals with HCV while neoplasms were more frequent in the same group (p = 0.02, p = 0.01, respectively). There were no differences in age, race, ethnicity, or treatment between IIM patients with and without HCV. Of the 11 patients that had HCV, 6 (55%) were diagnosed with HCV within 1 year of IIM diagnosis and majority (4/6) had active HCV at that time based on viral load. The others had been diagnosed with HCV for 5-10 years prior to the IIM diagnosis. For majority of HCV cases (6/11), rheumatology evaluation prompted hepatology evaluation and/or treatment. <h3>Conclusion</h3> Individuals with HCV may have different disease course than individuals without HCV, specifically one with a higher frequency of neoplasms and a lower frequency of ILD and dermatologic manifestations. IIM diagnosis was usually a key time to discover a concomitant HCV infection and often led to change in HCV evaluation and treatment. These findings and their immunologic basis should be further studied in larger cohorts with more power. <h3>References</h3> [1]Venalis P, Lundberg IE. Rheumatology (Oxford). 2014 Mar;53(3):397-405. [2]Uruha A, et aI. Neurology. 2016 Jan 19;86(3):211-7. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.